World may not be warming (news article)

[Cap'n Refsmmat]

An interesting article in the Times today:

http://www.timesonline.co.uk/tol/news/environment/article7026317.ece

 

“The temperature records cannot be relied on as indicators of global change,” said John Christy, professor of atmospheric science at the University of Alabama in Huntsville, a former lead author on the IPCC.

 

[...]

 

Christy has published research papers looking at these effects in three different regions: east Africa, and the American states of California and Alabama.

 

“The story is the same for each one,” he said. “The popular data sets show a lot of warming but the apparent temperature rise was actually caused by local factors affecting the weather stations, such as land development.”

 

[...]

 

Terry Mills, professor of applied statistics and econometrics at Loughborough University, looked at the same data as the IPCC. He found that the warming trend it reported over the past 30 years or so was just as likely to be due to random fluctuations as to the impacts of greenhouse gases. Mills’s findings are to be published in Climatic Change, an environmental journal.

 

Now, of course I realize that this does not represent the majority opinion of scientists or any conclusive disproof of global climate change. There are other records, like sea surface temperature readings, that can be checked against. (Also, how do you disprove that various glaciers are melting?) What would unreliable weather station readings mean for climate change?

 

Ordinarily I'd pose a "big" question at the end of this post, but I know how SFN responds to a climate change thread, so I'll just watch and wait.

[Moontanman]

Ok, if we are going to tease the tiger how about this one.

 

Humans may have prevented super ice age

 

Our impact on Earth's climate might be even more profound than we realise. Before we started pumping massive amounts of carbon dioxide into the atmosphere, the planet was on the brink of entering a semi-permanent ice age, two researchers have proposed.

 

Had we not radically altered the atmosphere, say Thomas Crowley of the University of Edinburgh, UK, and William Hyde of the University of Toronto in Canada, the current cycle of ice ages and interglacials would have given way in the not-too-distant future to an ice age lasting millions of years.

 

 

http://www.newscientist.com/article/dn16026-humans-may-have-prevented-super-ice-age.html

[jimmydasaint]

Capn - greetings. I don't know if you actually agree with what you have written or merely want to stimulate debate. Alternatively, you could be waiting to sucker someone into making a claim, whilst you swiftly demolish their arguments. I am going to maintain my fence sitting until I have serrated marks on my ass.

[Cap'n Refsmmat]

I'm staying out of either side. I don't think climate change can be falsified with a few simple objections, but then these objections seem to have significant merit. I'd rather wait for the dust to settle before deciding.

[jackson33]

In another related story breaking today, is the growing acceptance by pro-global warming scientist are accepting the 'Medieval Warm Period' (1000-1400AD), as a world wide phenomenon, which has long been accepted in the Northern Hemisphere (Greenland was green, etc).

 

An earlier warm period is attested in the archaeological record by finds such as Oetzi in the Alps. We know that thousands of years ago humans inhabited the lands now covered in glaciers; as the glaciers melt, we find evidence of their lives, and this would seem to contradict the argument that the Alpine glaciers have been there since the beginning of time. [/Quote]

 

http://phdiva.blogspot.com/2010/02/medieval-warm-period.html

 

 

Bluegrass Pundit This is a startling confession from 'Climategate' expert Phil Jones, The BBC is reporting Jones agrees two recent historic warm periods are similar to today and he can't say the Medieval Warm Period wasn't even warmer than today. BREAKING NEWS: CRU's Jones admits climate data problems, and Medieval Warm Period - TBR.cc Climate data 'not well organised': Prof Phil Jones - wildsingapore news From the BBC - Watts Up With That? See all 8 blogs. [/Quote]

 

Read more: http://upcoming.current.com/items/940869_climategate-expert-phil-jones-admits-medieval-warm-period-may-have-been-as-warm-or-warmer-than-present-and-related-posts.htm#ixzz0fYVRqBoZ

 

 

 

On the thread opening article, this is truly not news, James Hansen having been accused by several folks of doing/supporting the same things, one person supposedly Hansen's boss. I'm pretty sure I've posted here in 'Environmental' and will try to find tomorrow.

 

 

Jimmy; Cute... Why not take a shot at it and give an opinion, though it is curious when an Administrator enters a thread, knowing it's going to create a controversy. I'm biting, why not you...

[Pangloss]

Capn - greetings. I don't know if you actually agree with what you have written or merely want to stimulate debate. Alternatively, you could be waiting to sucker someone into making a claim, whilst you swiftly demolish their arguments.

 

Jimmy; Cute... Why not take a shot at it and give an opinion

 

Reminder: Due to its location on the board, this is not an opinion thread. This is a science thread. Discussion is limited to that basis.

 

Also, if you are interested in discussing the politics of global warming, please see various threads on the Politics subforum.

 

Thanks.

[Moontanman]

So far some pretty good ideas have been presented, no one has tried to give reasons they are not true, do we win?

[iNow]

An interesting article in the Times today:

Little more than crap from the denialist echo chamber.

 

http://scienceblogs.com/deltoid/2010/02/leakegate_scandal_gets_bigger.php

 

 

Not to mention that the locations which he claims were poorly sited actually... when analyzed... result in a cooling bias... not a warming bias as Christy contends.

 

http://www1.ncdc.noaa.gov/pub/data/ushcn/v2/monthly/menne-etal2010.pdf (pdf)

http://www.skepticalscience.com/On-the-reliability-of-the-US-Surface-Temperature-Record.html

[Cap'n Refsmmat]

Interesting. I'd love to see how this plays out.

[jackson33]

Not to mention that the locations which he claims were poorly sited actually... when analyzed... result in a cooling bias... not a warming bias as Christy contends.[/Quote]

 

Here is a site, showing the US locations, where urbanized and if you know the interstate highway system in the US, many follow that system. It also goes through the analyzing process, which is interesting and explains the reliability of some locations, around the world. As said, these questions have been being raised for many years, but will hold back on that earlier material.

 

Some nagging questions remained for Hansen and his colleagues. Citing issues such as stations located too close to paved surfaces, stations located in urban areas that are known to be warmer than rural regions, and stations located in developing nations where data collection methods may be unreliable, critics argued that any of these problems could throw off an individual station's temperature readings. Don't such concerns cast a shadow of doubt on the NOAA weather station data? [/Quote]

 

 

http://www.giss.nasa.gov/research/features/200711_temptracker/page2.html

 

 

Pangloss; Actually I was trying to add a bit of humor, BEFORE the thread went south, but will make this my last post on this thread....That should pretty well, eliminate any opposing viewpoint to AGW, guess what your wanting....

[swansont]

In another related story breaking today, is the growing acceptance by pro-global warming scientist are accepting the 'Medieval Warm Period' (1000-1400AD), as a world wide phenomenon, which has long been accepted in the Northern Hemisphere (Greenland was green, etc).

 

 

 

http://phdiva.blogspot.com/2010/02/medieval-warm-period.html

 

Oetzi dates to about 3300 BC, not the MWP, so that's only off by about 4500 years, and the assertion that it is claimed "Alpine glaciers have been there since the beginning of time" is a strawman.

 

http://en.wikipedia.org/wiki/Ötzi_the_Iceman

http://www.sciencedaily.com/releases/2009/01/090128074826.htm

[Tau Meson]

But what about this data mapping, which clearly shows that the temperature rose the greatest where there was little to no civilization-related activities near by (i.e. the North and South Poles):

 

 

 

 

 

The years 2000-2009 was by far the warmest decade on record, and it is not unreasonable to conclude that, well, the world is warming up and burning...

Edited February 15, 2010 by Tau Meson

[SH3RL0CK]

Check out this news story:

 

http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html

 

The academic at the centre of the ‘Climategate’ affair, whose raw data is crucial to the theory of climate change, has admitted that he has trouble ‘keeping track’ of the information... he may have actually lost the relevant papers.

 

The data is crucial to the famous ‘hockey stick graph’ used by climate change advocates to support the theory.

 

Professor Jones also conceded the possibility that the world was warmer in medieval times than now – suggesting global warming may not be a man-made phenomenon.

And he said that for the past 15 years there has been no ‘statistically significant’ warming

(emphasis mine)

 

If true, this news story would appear to change everything.

 

I still think GW is still occuring (what else would the excess atmospheric CO2 do?) but without accurate data we simply know much less about this issue than we thought we did.

 

And with no warming for the past 15 years, no original data previous to this timeframe for verification checks, should the public be expected to enact expensive behavior modifications and carbon trades? I would think not.

 

 

It is also fuel for the skeptics:

But Dr Benny Pieser, director of the sceptical Global Warming Policy Foundation, said Professor Jones’s ‘excuses’ for his failure to share data were hollow as he had shared it with colleagues and ‘mates’.

He said that until all the data was released, sceptics could not test it to see if it supported the conclusions claimed by climate change advocates.

He added that the professor’s concessions over medieval warming were ‘significant’ because they were his first public admission that the science was not settled.

 

[jimmydasaint]

This bit makes me a bit worried but then I have to take into account all verifiable data. Therefore I am still sitting on the fence.

 

Professor Jones also conceded the possibility that the world was warmer in medieval times than now – suggesting global warming may not be a man-made phenomenon.

 

Read more: http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html#ixzz0fjmQ43Dt

 

This suggests that medieval British people could have been growing grapes for wine etc.. and that the natural flora and fauna here must have been quite different to what we see now.

[swansont]

If true, this news story would appear to change everything.

 

But it's not true. It's culled out of context from the interview. Basically what he said was that the warming since 1995 is about the same as the weather noise. Over such a short period of time you could not statistically conclude there was warming, since it's possible that it's the noise — just barely (it's right at the edge of being statistically significant). i.e. the best fit is a positive slope (0.12 C per decade), but you could just barely draw a zero-slope line and have it be statistically acceptable. But, under those conditions, you could also draw a line with twice the slope (.24 C per decade) and it would have the same statistical significance as the zero slope line. So you must apply equal weight to the probability that there is no warming as to the probability that it's twice as bad as advertised, and you have no scientific support for concluding one over the other. Which is why you have to look at the longer-term.

 

And over a longer period of time, the warming is statistically significant.

 

Here's the actual interview, rather than the "interpretation" (that has apparently undergone a sciencectomy) of it:

 

http://news.bbc.co.uk/2/hi/science/nature/8511670.stm

[jryan]

But it's not true. It's culled out of context from the interview. Basically what he said was that the warming since 1995 is about the same as the weather noise. Over such a short period of time you could not statistically conclude there was warming, since it's possible that it's the noise — just barely (it's right at the edge of being statistically significant). i.e. the best fit is a positive slope (0.12 C per decade), but you could just barely draw a zero-slope line and have it be statistically acceptable. But, under those conditions, you could also draw a line with twice the slope (.24 C per decade) and it would have the same statistical significance as the zero slope line. So you must apply equal weight to the probability that there is no warming as to the probability that it's twice as bad as advertised, and you have no scientific support for concluding one over the other. Which is why you have to look at the longer-term.

 

And over a longer period of time, the warming is statistically significant.

 

Here's the actual interview, rather than the "interpretation" (that has apparently undergone a sciencectomy) of it:

 

http://news.bbc.co.uk/2/hi/science/nature/8511670.stm

 

You are claiming that the 15 year claim isn't true because it's wrong on longer time scales. That is like saying that an apple isn't an apple because oranges are oranges.

 

And is the warming significant over even longer time scales? Jones has an interesting statement there (emphasis mine):

 

There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia. For it to be global in extent the MWP would need to be seen clearly in more records from the tropical regions and the Southern Hemisphere. There are very few palaeoclimatic records for these latter two regions.

 

So if we have too few paleoclimatic records to establish SH and Tropical climate during the NH MWP then what exactly do we know about paleoclimate at all?

[Pangloss]

In reference to post #12 above, I wonder why warming would be greater in places where there is the least human civilization? It occurs to me that this is not necessarily a reflection on human influence (i.e. it doesn't mean that man didn't cause it). Is it possible that the energy that causes the warming is created in one place, but then essentially "pools" in another area, causing that area to warm instead?

 

(I'm thinking along the lines of the way energetic particles spread heat more rapidly than placid ones. Or to borrow another metaphor, those great trash circles out in the ocean -- they weren't created there, but their contents obviously come from human beings.)

[swansont]

You are claiming that the 15 year claim isn't true because it's wrong on longer time scales. That is like saying that an apple isn't an apple because oranges are oranges.

 

No, that's not what I claimed. You appear to have completely missed the point.

 

The warming in the time span in question was given as .12 C/decade, but also that it was just barely consistent with zero, meaning one could present it as .12 ± .12C C/decade, where the uncertainty represents a 95% confidence interval.

 

So the best fit to the data is a positive slope of .12C C/decade. One could also say it is consistent with zero, but one must, at the same time, acknowledge that it is consistent with .24 C/decade. One cannot advance one extreme over the other. Meaning that the statement "it has not warmed since 1995" is not supportable from the numbers — you can draw NO conclusions whatsoever. The Daily Mail reporter/editor apparently did not have the scientific literacy requisite to recognize this.

 

Now the funny thing about statistical fluctuations is that they average out as you get more data, and are reduced with the square root of the number of data points. So e.g. a data set twice as long (but otherwise identical in nature) is going to have 70% of the noise — IOW, of one looks at 30 years instead of 15, one would expect an uncertainty of .08 C, and now you have an increase of .12 ± .08 C/decade, and now zero is statistically excluded.

 

So you need to look at a longer set of data to see a statistically significant trend. This is not surprising to anyone with a passing familiarity with statistics. Focusing on the short term only leaves you with "we can't tell from this data set." Which is why many of the graphs presented use averaged data, so you can actually draw conclusions from them.

 

 

And is the warming significant over even longer time scales? Jones has an interesting statement there (emphasis mine):

 

 

 

So if we have too few paleoclimatic records to establish SH and Tropical climate during the NH MWP then what exactly do we know about paleoclimate at all?

 

There is this persistent thought that if it was warmer in the past than it is now, that somehow AGW is false. I can't fathom the tortured, faulty logic that would allow one to come to this conclusion. If it was warmer, there must be a physical cause — the energy has to come from somewhere. In our current situation, the best science says it's from the CO2 greenhouse effect. If you reject that, you need to come up with the missing energy. Saying "it's natural variation" is not a substitute — "natural" effects can and must still be identified and quantified.

[jryan]

No, that's not what I claimed. You appear to have completely missed the point.

 

The warming in the time span in question was given as .12 C/decade, but also that it was just barely consistent with zero, meaning one could present it as .12 ± .12C C/decade, where the uncertainty represents a 95% confidence interval.

 

So the best fit to the data is a positive slope of .12C C/decade. One could also say it is consistent with zero, but one must, at the same time, acknowledge that it is consistent with .24 C/decade. One cannot advance one extreme over the other. Meaning that the statement "it has not warmed since 1995" is not supportable from the numbers — you can draw NO conclusions whatsoever. The Daily Mail reporter/editor apparently did not have the scientific literacy requisite to recognize this.

 

Now the funny thing about statistical fluctuations is that they average out as you get more data, and are reduced with the square root of the number of data points. So e.g. a data set twice as long (but otherwise identical in nature) is going to have 70% of the noise — IOW, of one looks at 30 years instead of 15, one would expect an uncertainty of .08 C, and now you have an increase of .12 ± .08 C/decade, and now zero is statistically excluded.

 

So you need to look at a longer set of data to see a statistically significant trend. This is not surprising to anyone with a passing familiarity with statistics. Focusing on the short term only leaves you with "we can't tell from this data set." Which is why many of the graphs presented use averaged data, so you can actually draw conclusions from them.

 

This is complete rubbish if climate is driven predominantly by cyclical forcings.

 

 

 

 

There is this persistent thought that if it was warmer in the past than it is now, that somehow AGW is false. I can't fathom the tortured, faulty logic that would allow one to come to this conclusion. If it was warmer, there must be a physical cause — the energy has to come from somewhere. In our current situation, the best science says it's from the CO2 greenhouse effect. If you reject that, you need to come up with the missing energy. Saying "it's natural variation" is not a substitute — "natural" effects can and must still be identified and quantified.

 

It is not tortured and faulty logic given that the reason we even care about AGW is that it is abnormal, if AGW resulted in variations within accepted natural limits, even if anthropogenic, then their is no reason to be concerned.

 

It is also important because the basis of the entire run-away warming theory is that the climate system can no longer self regulate due to anthropogenic influences. If it CAN regulate then whether or not AGW is true is irrelevant and the study returns to being an academic exercise that no longer requires a heavily funded IPCC, Cap-and-Trade, etc. etc.

 

Also, if "the best science" says that the last 150 years of warming is from anthropogenic CO2 GHE then what would the Earth's climate trend have been absent anthropogenic CO2? Stasis? Cooling? By your argument you have ruled out warming.

[SH3RL0CK]

But it's not true. It's culled out of context from the interview. Basically what he said was that the warming since 1995 is about the same as the weather noise. Over such a short period of time you could not statistically conclude there was warming, since it's possible that it's the noise — just barely (it's right at the edge of being statistically significant). i.e. the best fit is a positive slope (0.12 C per decade), but you could just barely draw a zero-slope line and have it be statistically acceptable. But, under those conditions, you could also draw a line with twice the slope (.24 C per decade) and it would have the same statistical significance as the zero slope line. So you must apply equal weight to the probability that there is no warming as to the probability that it's twice as bad as advertised, and you have no scientific support for concluding one over the other. Which is why you have to look at the longer-term.

 

And over a longer period of time, the warming is statistically significant.

 

I don't disagree with this; it is a reasonable explaination. More data (and more time) will indeed clarify the direction and extent of the climate change.

Here's the actual interview, rather than the "interpretation" (that has apparently undergone a sciencectomy) of it:

 

http://news.bbc.co.uk/2/hi/science/nature/8511670.stm

 

Hmmm. After reading this, I'm not encouraged. The actions taken and explainations provided in defense of these actions seem rather lame to me. See for example:

 

The phrase 'hide the decline' was shorthand for providing a composite representation of long-term temperature changes made up of recent instrumental data and earlier tree-ring based evidence, where it was absolutely necessary to remove the incorrect impression given by the tree rings that temperatures between about 1960 and 1999 (when the email was written) were not rising, as our instrumental data clearly showed they were.

 

This "divergence" is well known in the tree-ring literature and "trick" did not refer to any intention to deceive - but rather "a convenient way of achieving something", in this case joining the earlier valid part of the tree-ring record with the recent, more reliable instrumental record.

I'm going to have to look into the issue about the tree-ring divergence more. I'm curious as to why would this data be valid 1000 years ago, but not considered valid (even given that we have more accurate information) 60 years ago?

 

R - Why did you ask a colleague to delete all e-mails relating to the Fourth Assessment Report of the IPCC?

 

This was an e-mail sent out of frustration at one FOI request that was asking for the e-mail correspondence between the lead authors on chapter six of the Working Group One Report of the IPCC. This is one of the issues which the Independent Review will look at.

 

Really now. Why not simply ask the colleage to foward these e-mails directly to the person requesting the information? That is the same amount of work. Granted the skeptic will no doubt look for "gotcha" statements, but that goes with the respect they have been given such that various governments are going to spend $billions (or $Trillions) based on their work. If they were acting in good faith (and I still think they were) these "gotcha" statements would be easier to address than then current credibility crisis and they should have realized that at the time.

 

U - Now, on to the fallout from "Climategate", as it has become known. You had a leading role in a part of the IPCC, Working Group I. Do you accept that credibility in the IPCC has been damaged - partly as a result of your actions? Does the IPCC need reform to gain public trust?

 

Some have said that the credibility in the IPCC has been damaged, partly due to the misleading and selective release of particular e-mails. I wish people would spend as much time reading my scientific papers as they do reading my e-mails. The IPCC does need to reassure people about the quality of its assessments.

His statement is absolutely wrong. Of couse the IPCC need to reassure people about the quality of its assessments. Why else is this man being interviewed? And besides, various governments are intending to spend $Billions based on their data. Sorry, he doesn't get to brush aside these questions that easily.

 

I also notice the "lost data" wasn't addressed in the interview...I wonder where the daily mail got that from the interview?

 

I'm still not doubting some level of AGW exists, based on the above I am more skeptical than before about the projections. I agree we must take action. However, I have always questioned the accuracy of the projections and the apparently extremely urgent need to enact futile (and expensive only to the USA and to a lesser extent EU) attempts to correct what might or might not be a serious problem. A better idea might be a gradual shift to renewable energy that both the West and 3rd world countries could afford rather than increasing the CO2 output by shifting all manufacturing to inefficient factories in India and China.

Edited February 17, 2010 by SH3RL0CK
correction of typo

[swansont]

I don't disagree with this; it is a reasonable explaination. More data (and more time) will indeed clarify the direction and extent of the climate change.

 

 

But that's just it — we do have more data. The statement that was bastardized referred to warming since 1995. Once you look at several decades, the signal is no longer masked by the noise.

 

As to the rest, we already had a thread on the email issues, and I think it's off-topic for this particular thread. I was discussing/debunking the specific claim in the article in the Daily Mail. They made it sound like Jones was saying one thing, when he said something quite different.

[SH3RL0CK]

But that's just it — we do have more data. The statement that was bastardized referred to warming since 1995. Once you look at several decades, the signal is no longer masked by the noise.

I agree, clearly the world is warmer now than in the past. The real question that is unanswered is what should we do, now we know the earth is warming? What I question based on the information in the links is the accuracy of the projections; because the severity of the problem affects what we should do. Do we need a crash program to address this, or do we have time to gradually phase in a more sustainable society? These relevations do not give me confidence we have quantified the severity of the problem ... as for

 

As to the rest, we already had a thread on the email issues, and I think it's off-topic for this particular thread. I was discussing/debunking the specific claim in the article in the Daily Mail. They made it sound like Jones was saying one thing, when he said something quite different.

I also agree, and since we have drifted off topic I'll stop it here.

[ParanoiA]

The argument I'm getting is coming from the American Thinker:

 

http://www.americanthinker.com/2010/02/the_agw_smoking_gun.html

 

So what type of experiment could be performed to test this AGW hypothesis? If there were satellites in orbit monitoring the emission of OLR over time at the same location, then OLR could be measured in a very controlled manner. If, over time, the emission of OLR in the wavelengths that CO2 absorbs decreases over time, then that would prove the AGW hypothesis (i.e., that OLR is being absorbed by CO2 and heating the planet instead of being emitted from the atmosphere). But what if, over time (say, over thirty years), the emissions of OLR wavelengths that CO2 absorb remained constant? That would disprove the hypothesis and put the AGW argument to bed.

 

As luck would have it, that experiment has actually been performed! Three journal papers report the data from three monitoring satellites that have measured the OLR of 1997 and 2006 and compared those measurements to 1970, and they are located here, here, and here.

 

There were three different experiments performed in space to measure OLR emissions. The Infrared Interferometer Spectrometer (IRIS) was performed in 1970, the Interferometer Monitor of Greenhouse Gases (IMG) was performed in 1997, and the Tropospheric Emission Spectrometer (TES) was performed in 2006. All of these experiments were performed over the Pacific Ocean and confined to the same three-month period (April through June), and the data were limited to cloudless days. The variable measured was brightness temperature, which is given in degrees Kelvin (K). Higher brightness temperatures correlate to higher emissions (meaning that more OLR is emitted to the atmosphere and less is absorbed by GHG).

 

So the results of three different peer-reviewed papers show that over a period of 36 years, there is no reduction of OLR emissions in wavelengths that CO2 absorb. Therefore, the AGW hypothesis is disproven.

 

First of all, I'm not sure how to counter this argument. I know that Lindzen and Choi have been proven wrong before and I remember someone posting a link here a few months ago that linked to a rebuttal of a paper of theirs on measuring the heat radiating off of the planet, post peer-review if I remember correctly.

 

I strongly suspect that same paper was used in these "three points" mentioned above, 1997, 2006 "compared" with 1970, whatever that's supposed to mean.

 

 

Second of all, this sentence strikes me as problematic:

 

If the solar activity is taken to remain constant, more CO2 in the atmosphere will trap more of the OLR, and thus cause a net heating of the planet.

 

Do we take the solar activity to remain constant? Does the input energy remain relatively constant? It would seem to me that you couldn't go by simply measuring OLR emmissions if the input is variable. I don't know...

 

There are lot of people running around about this OLR emmission and how there must be a decrease otherwise the theory is invalid. If there really wasn't any decrease in OLR emmission, would that be a true conclusion?

---

Merged post follows:

Consecutive posts merged

But it's not true. It's culled out of context from the interview. Basically what he said was that the warming since 1995 is about the same as the weather noise. Over such a short period of time you could not statistically conclude there was warming, since it's possible that it's the noise — just barely (it's right at the edge of being statistically significant). i.e. the best fit is a positive slope (0.12 C per decade), but you could just barely draw a zero-slope line and have it be statistically acceptable. But, under those conditions, you could also draw a line with twice the slope (.24 C per decade) and it would have the same statistical significance as the zero slope line. So you must apply equal weight to the probability that there is no warming as to the probability that it's twice as bad as advertised, and you have no scientific support for concluding one over the other. Which is why you have to look at the longer-term.

 

And over a longer period of time, the warming is statistically significant.

 

Here's the actual interview, rather than the "interpretation" (that has apparently undergone a sciencectomy) of it:

 

http://news.bbc.co.uk/2/hi/science/nature/8511670.stm

 

If the amount of warming wasn't significant enough statistically over the last 15 years, then how bad is global warming? If it's only warming at a rate that equals the weather noise, then how is that significant on a longer term?

[swansont]

If the amount of warming wasn't significant enough statistically over the last 15 years, then how bad is global warming? If it's only warming at a rate that equals the weather noise, then how is that significant on a longer term?

 

Noise is bounded. The warming is larger than the noise on longer time scales. The number given is 0.12 C/decade. Which means 0.6 C in 50 years, all else being equal, and a similar length data set then will still have about .12 C of noise, but the average will be 0.6 C higher.